This invention relates to computer peripheral testing equipment.
Conventional computer peripheral testing equipment normally involves the host computer or test means internally of the peripheral equipment or dedicated logic circuitry specific to only one type of peripheral. In the first case, test software is provided for the host computer which provides a sequence of tests normally under control of the user. Any defect in the host computer can affect results, so that this does not always provide a reliable test method. In the second case, interface circuitry in the peripheral will not normally be incorporated in the test so that a defect there will not be directly exposed. In the third case, there is lack of flexibility.
U.K. patent specification No. 1356324, for an Electronic Circuit Tester, discloses a special purpose electronic circuit tester comprising a programmable computer containing a test pattern. This is a chip tester to allow individual chips in a memory array to be tested. It is not designed for testing peripherals.
U.K. patent specification No. 1328978 discloses electronic unit testing equipment for use with a computer to provide a system for testing printed circuit cards by applying stimulus to a board in a manner controlled by the computer and by comparing the results with a stored norm. Computer peripherals as such do not in general seem to be catered for by this equipment. Thus, it not only suffers from the disadvantage mentioned above of requiring a host computer but also it seems not to be designed to test and exercise a variety of peripherals as such.
U.K. patent specification No. 1403710 discloses a general purpose computer which is not designed for peripheral testing as such but which can have self-diagnosis and, like other general computers, can be coupled to operate a variety of peripherals via respective dedicated input/output connectors.
The programming of the computer may be altered by changing plug-in program modules which can alter the functions of keys of a keyboard of the computer e.g. to give different typewriter functions. The computer, being general purpose, is somewhat expensive and unwieldy for use as an engineer's diagnostic tool and, indeed, is not designed as such.
It is an object of the invention to provide a self-contained, portable, engineer's diagnostic tool by which computer peripherals can be tested and exercised independently of their host computer.